U.S. patent number 8,528,710 [Application Number 13/081,202] was granted by the patent office on 2013-09-10 for mobile type non-contact power feeding device.
This patent grant is currently assigned to Showa Aircraft Industry Co., Ltd.. The grantee listed for this patent is Keisuke Abe, Masashi Mochizuki, Yasuyuki Okiyoneda, Takeshi Sato, Kitao Yamamoto. Invention is credited to Keisuke Abe, Masashi Mochizuki, Yasuyuki Okiyoneda, Takeshi Sato, Kitao Yamamoto.
United States Patent |
8,528,710 |
Yamamoto , et al. |
September 10, 2013 |
Mobile type non-contact power feeding device
Abstract
A non-contact power feeding device feeds power from a power
transmission coil to a power receiving coil based on a mutual
induction effect of electromagnetic induction. In such a
non-contact power feeding device, power can be fed to the power
receiving coil by a mobile power feeding method whereby the power
receiving coil is moved corresponding to the stationary power
transmission coil through an air gap in the case of power feeding.
The power transmission coil and the power receiving coil are
respectively formed in a loop-shaped flat structure. A crossover
coil is adopted to serve as the power transmission coil. The
crossover coil is formed in a long loop shape along the direction
of movement of the power receiving side and is crossed along the
way to provide a plurality of units. It is however to be noted that
a resonant repeating coil can be used together with the power
transmission coil to adopt the crossover coil as its repeating
coil.
Inventors: |
Yamamoto; Kitao (Akishima,
JP), Sato; Takeshi (Akishima, JP), Abe;
Keisuke (Akishima, JP), Mochizuki; Masashi
(Akishima, JP), Okiyoneda; Yasuyuki (Akishima,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Yamamoto; Kitao
Sato; Takeshi
Abe; Keisuke
Mochizuki; Masashi
Okiyoneda; Yasuyuki |
Akishima
Akishima
Akishima
Akishima
Akishima |
N/A
N/A
N/A
N/A
N/A |
JP
JP
JP
JP
JP |
|
|
Assignee: |
Showa Aircraft Industry Co.,
Ltd. (Tokyo, JP)
|
Family
ID: |
44118365 |
Appl.
No.: |
13/081,202 |
Filed: |
April 6, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110248574 A1 |
Oct 13, 2011 |
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Foreign Application Priority Data
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Apr 7, 2010 [JP] |
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2010-088411 |
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Current U.S.
Class: |
191/10;
191/18 |
Current CPC
Class: |
H02J
5/005 (20130101); H02J 7/025 (20130101); H02J
50/50 (20160201); H02J 50/70 (20160201); H02J
50/12 (20160201); Y02T 10/70 (20130101); Y02T
10/7072 (20130101); Y02T 90/14 (20130101) |
Current International
Class: |
B60L
9/00 (20060101); B60M 1/00 (20060101) |
Field of
Search: |
;191/2,6,10,13,14,17,18,22R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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6-335117 |
|
Dec 1994 |
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JP |
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2009-071909 |
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Apr 2009 |
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JP |
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WO-92/17929 |
|
Oct 1992 |
|
WO |
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WO-98/50993 |
|
Nov 1998 |
|
WO |
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WO-2007/008646 |
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Jan 2007 |
|
WO |
|
Primary Examiner: McCarry, Jr.; R. J.
Attorney, Agent or Firm: Jordan and Hamburg LLP
Claims
What is claimed is:
1. An apparatus for non-contact feeding of power by electromagnetic
induction, the apparatus comprising: a crossover coil serving as a
stationary power transmission coil of a power feeding circuit; and
a power receiving coil of a power receiving circuit; and wherein
said non-contact feeding of power by electromagnetic induction is
from said power transmission coil to said power receiving coil;
wherein the power receiving coil is arranged to move relative to
the stationary power transmission coil through an air gap, the
power receiving coil comprising a flat loop; wherein the crossover
coil has an array of a plurality of flat loops elongated in a
direction of movement, each one loop of the plurality of flat loops
being separated from each other by a crossover, each one loop of
the plurality of flat loops of the crossover coil being a unit; and
wherein crossovers of the crossover coil effect a reversal of
direction of a magnetic field being generated by the units between
a plus direction and a minus direction from each one unit to each
next unit of the units of the crossover coil.
2. The apparatus according to claim 1, wherein the units generating
the magnetic field in the plus direction at a given time have an
area equal to that of the units generating magnetic field in the
minus direction at said given time.
3. The apparatus according to claim 1, wherein a repeating coil of
a repeating circuit is fixedly disposed relative to the power
receiving coil of the power receiving circuit, the repeating
circuit is independent of the power receiving circuit, and the
repeating coil resonates with a capacitor disposed in the repeating
circuit and moves together with the power receiving coil.
4. The apparatus according to claim 1, wherein the power
transmission coil of the power feeding circuit is fixedly disposed
alongside and above a road surface or a ground surface.
5. The apparatus according to claim 1, wherein the power
transmission coil of the power feeding circuit is fixedly disposed
on or embedded in a road surface or a ground surface.
6. The apparatus according to claim 1, wherein the power receiving
coil of the power receiving circuit is mounted on a vehicle or
other movable body.
7. An apparatus for non-contact feeding of power by electromagnetic
induction, the apparatus comprising: a stationary power
transmission coil of a power feeding circuit; and a power receiving
coil of a power receiving circuit; and wherein said non-contact
feeding of power by electromagnetic induction is from said power
transmission coil to said power receiving coil; wherein the power
receiving coil is arranged to move relative to the stationary power
transmission coil through an air gap; wherein the power receiving
coil and the power transmission coil each comprises a flat loop;
wherein a repeating coil of a repeating circuit is fixedly disposed
relative to the power transmission coil, the repeating circuit
being independent of the power feeding circuit, the repeating coil
resonating with a capacitor disposed in the repeating circuit;
wherein the power receiving coil is arranged to move relative to
the repeating coil through the air gap for power feeding; wherein
the repeating coil is a crossover coil having an array of a
plurality of flat loops elongated in a direction of said movement;
wherein each one loop of the plurality of flat loops is separated
from each other by a crossover, each one loop of the plurality of
flat loops of the crossover coil being a unit; and wherein a
direction of a magnetic field being generated by units formed by
crossovers of the crossover coil is alternately reversed in a plus
direction and a minus direction.
8. The apparatus according to claim 7, comprising a capacitor for
each unit of the repeating coil.
9. The apparatus according to claim 7, wherein the units generating
the magnetic field in the plus direction at a given time have an
area equal to that of the units generating magnetic field in the
minus direction at said given time.
10. The apparatus according to claim 7, wherein a repeating coil of
a second repeating circuit is fixedly disposed relative to the
power receiving coil of the power receiving circuit, the second
repeating circuit is independent of the power receiving circuit,
and the repeating coil of the second repeating circuit resonates
with a capacitor disposed in the second repeating circuit and moves
together with the power receiving coil.
11. The apparatus according to claim 7, wherein the power
transmission coil of the power feeding circuit and the repeating
coil of the repeating circuit are fixedly disposed alongside or
above a road surface or a ground surface.
12. The apparatus according to claim 7, wherein the power
transmission coil of the power feeding circuit and the repeating
coil of the repeating circuit are fixedly disposed on or embedded
in a road surface or a ground surface.
13. The apparatus according to claim 7, wherein the power receiving
coil of the power receiving circuit is mounted on a vehicle or
other movable body.
14. An apparatus for non-contact feeding of power by
electromagnetic induction, the apparatus comprising: a plurality of
stationary coils of a power feeding circuit, each one of the
plurality of stationary coils comprising a plurality of flat loops
elongated in a common first direction and being delimited from an
adjacent one of the plurality of stationary coils by a crossover,
the plurality of stationary coils formed by a common conductor and
together forming a stationary power transmission coil; and a power
receiving coil of a power receiving circuit configured to move in
said first direction through an air gap, said movement being
relative to the stationary power transmission coil, the power
receiving coil comprising a flat loop, said non-contact feeding of
power by electromagnetic induction being from said stationary power
transmission coil to said moving power receiving coil; and wherein
each crossover between adjacent ones of the plurality of stationary
coils effects a reversal of direction of a magnetic field being
generated by said adjacent ones of the plurality of stationary
coils between one of a plus direction and a minus direction and
another of the plus direction and the minus direction so that
adjacent coils of the plurality of stationary coils generate
different magnetic field polarity.
15. The apparatus of claim 14, wherein adjacent stationary coils of
the stationary power transmission coil are connected in series by
the crossover delimiting the adjacent stationary coils.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a mobile type non-contact power
feeding device, and more particularly to a non-contact power
feeding device adapted to feed power, with no contact, to a moving
secondary side, that is, a power receiving side or a pickup side
from a stationary primary side, that is, a power feeding side or a
track side.
A non-contact power feeding device adapted to feed power to, for
example, a battery of an electric vehicle without any mechanical
contact such as a cable has been developed based on the demand and
this device is in practical use.
In this non-contact power feeding device, power is fed through an
air gap in a closely corresponding manner to a power receiving coil
of a power receiving side mounted on a movable body such as an
electric vehicle from a stationary power transmission coil of a
power feeding side based on a mutual induction effect of
electromagnetic induction.
A stopped type power feeding method is a representative example for
feeding power by the non-contact power feeding device, but a
convenient mobile type power feeding method which is not required
to purposely stop for power feeding has also been developed and
this method is in practical use.
Referring to the stopped type power feeding method, the movable
body is required to stop in the case of power feeding and the power
receiving coil is positioned to stop on or over the power
transmission coil to feed power. On the contrary, in the mobile
type power feeding method, the movable body is not required to stop
in the case of power feeding and power feeding is effected while
the power receiving coil is moving near the power transmission
coil.
The technology disclosed in the following Japanese Unexamined
Patent Publication No. H06-506099 (Japanese translation of PCT
international application) is a representative example of a mobile
type non-contact power feeding device.
However, this non-contact power feeding device is suitable for an
automated guided vehicle which is used in a factory and the like,
but there is a disadvantage that it is not suitable for use in an
electric vehicle which is running on a road. In other words, the
power receiving coil of the power receiving side is required to
move through an extremely-close small air gap relative to the
stationary power transmission coil of the power feeding side.
In order to overcome such a disadvantage of the non-contact power
feeding device as disclosed in Japanese Unexamined Patent
Publication No. H06-506099 (Japanese translation of PCT
international application), the technologies disclosed in the
following Japanese Unexamined Patent Publication No. 2002-508916
(Japanese translation of PCT international application) and
Japanese Unexamined Patent Publication No. 2009-501510 (Japanese
translation of PCT international application) have been
developed.
The technologies disclosed in Japanese Unexamined Patent
Publication No. 2002-508916 (Japanese translation of PCT
international application) and Japanese Unexamined Patent
Publication No. 2009-501510 (Japanese translation of PCT
international application) are characterized in that an independent
repeating circuit is provided to serve as a resonant circuit on a
power feeding side and/or a power receiving side, and a repeating
coil of the resonant circuit is disposed in a magnetic path of the
air gap. With this arrangement, the mobile type non-contact power
feeding device composed of this resonant repeating method enables
power supply through a large air gap and is suitable for feeding
power to, for example, an electric vehicle.
It has been pointed out that the mobile type non-contact power
feeding device has the following problems.
In the non-contact power feeding device, power feeding is conducted
based on a mutual induction effect of electromagnetic induction.
Since a high frequency magnetic field (an alternate-current
variable magnetic field) is strongly formed to radiate and diffuse
high frequency electromagnetic waves at a strong intensity, there
is a possibility that this has an adverse affect on the neighboring
environment.
For example, in an area which is tens of meters to hundreds of
meters away, it has been pointed out that there is a risk that
electromagnetic pollution such as possible electromagnetic
disturbance and electronic jamming are caused and a risk that
dysfunction is created on human bodies.
Under these circumstances, for example, in Japan, the Radio Law
sets limits on facilities where a high frequency of 10 kHz or more
is used to make the intensity of electromagnetic waves radiated
from these facilities less than or equal to the regulatory
value.
On the contrary, in the case of the stopped type non-contact power
feeding device described above, it is easy to take measures for
electromagnetic shielding. In other words, since a loop of the
power transmission coil of the power feeding side is small, by
covering the power transmission coil with an electromagnetic-wave
shielding cover in which an electrically conductive material is
used, it is easy to reflect, absorb and attenuate the radiated
electromagnetic waves to the regulatory value level or lower.
On the contrary, in the case of the mobile type non-contact power
feeding device, it is difficult to take measures for the
electromagnetic shielding.
In other words, the power transmission coil of the power feeding
side, in view of the fact that the power receiving side is moving,
is formed in a long and massive loop shape along the direction of
movement and has a large loop area. In this manner, it is not easy
to take such an electromagnetic shielding measure as to cover the
power transmission coil with the electromagnetic shielding cover
and as a result, it is easy for the radiated electromagnetic waves
to reach a neighboring area.
Accordingly, a conventional mobile type non-contact power feeding
device has been set and used in a range in which the usable
frequency does not exceed the regulatory value, that is, 10
kHz.
Referring to the non-contact power feeding device, expansion of an
air gap is a major theme in view of the needs such as widespread
utilization of the electric vehicles.
Even in the mobile type non-contact power feeding device, the
technologies disclosed in Japanese Unexamined Patent Publication
No. 2002-508916 (Japanese translation of PCT international
application) and Japanese Unexamined Patent Publication No.
2009-501510 (Japanese translation of PCT international application)
described above have been developed in view of such needs and
themes, but because of adoption of the resonant repeating method,
those technologies are premised on the use of a high frequency AC
of 10 kHz or more, for example, a high frequency AC of the degree
of tens of kHz to 100 kHz, from the aspect of efficiency.
Accordingly, if this mobile type non-contact power feeding device
is adopted, as is, to feed power to an electric vehicle which is
running on an express highway or other roads, the electromagnetic
waves radiated outside become stronger to have a greater risk of
generating the electromagnetic pollution described above. It is
therefore quite difficult to adopt the mobile type non-contact
power feeding device under the existing conditions because of the
problems described above.
SUMMARY OF THE INVENTION
A mobile type non-contact power feeding device of the present
invention was developed to solve the problems of the conventional
technology in view of the actual conditions thereof.
It is therefore an object of the present invention to provide an
improved mobile non-contact power feeding device in which, first,
there is no risk of electromagnetic pollution and, second,
expansion of an air gap can be realized and which, third, can
contribute to the widespread utilization of an electric
vehicle.
A technical means of the present invention for solving these
problems is described below and claimed.
(Aspect 1)
A mobile type non-contact power feeding device is provided, in
which power is fed from a power transmission coil of a power
feeding side circuit to a power receiving coil of a power receiving
side circuit based on a mutual induction effect of electromagnetic
induction.
Power can be fed to the power receiving coil by a mobile power
feeding method whereby the power receiving coil is moved
corresponding to the stationary power transmission coil through an
air gap.
The power transmission coil and the power receiving coil are
respectively formed in a loop-shaped flat structure and a crossover
coil is adopted to serve as the power transmission coil.
The crossover coil is formed in a long loop shape along the
direction of movement of the power receiving side and is crossed
along the way to provide a number of units.
Further, as described in the following aspects 2 through 15, the
mobile type non-contact power feeding device according to the
present invention can be modified by adding technically limited
elements.
(Aspect 2)
In the mobile type non-contact power feeding device according to
aspect 1, the crossover coil is provided in such a manner that a
magnetic field is generated from the units formed by the crossover
alternately in the plus and minus directions.
(Aspect 3)
In the mobile type non-contact power feeding device according to
aspect 2, the crossover coil is set in such a manner that the area
of the units generating a magnetic field in the plus direction is
equal to that of the units generating a magnetic field in the minus
direction.
(Aspect 4)
In the mobile type non-contact power feeding device according to
aspect 1, a repeating coil of a repeating circuit is disposed
corresponding to the power receiving coil of the power receiving
side circuit.
The repeating circuit is independent of the power receiving side
circuit and the repeating coil resonates with a capacitor disposed
in the repeating circuit and moves together with the power
receiving coil.
(Aspect 5)
In the mobile type non-contact power feeding device according to
aspect 1, power feeding is effected by a side power feeding method
whereby the power transmission coil of the power feeding side
circuit is fixedly disposed on the side of an upright roadside
section relative to a road surface or a ground surface.
(Aspect 6)
In the mobile type non-contact power feeding device according to
aspect 1, power feeding is effected by a lower power feeding method
whereby the power transmission coil of the power feeding side
circuit is fixedly disposed on the side of a road surface or a
ground surface.
(Aspect 7)
In the mobile type non-contact power feeding device according to
aspect 1, the power receiving side circuit such as the power
receiving coil is mounted on a vehicle such as an automobile or
other movable body.
(Aspect 8)
In the mobile type non-contact power feeding device according to
aspect 1, a repeating coil of a repeating circuit is fixedly
disposed corresponding to the power transmission coil. The
repeating circuit is independent of the power feeding side circuit
and the repeating coil resonates with a capacitor disposed in the
repeating circuit. In the case of power feeding, the power
receiving coil moves corresponding to the repeating coil through an
air gap.
The crossover coil as in aspect 1 is not adopted to serve as the
power transmission coil of the power feeding side circuit. Instead,
the crossover coil is adopted to serve as the repeating coil of the
repeating circuit.
(Aspect 9)
In the mobile type non-contact power feeding device according to
aspect 8, a capacitor of the repeating circuit is disposed for each
unit of the repeating coil consisting of the crossover coil.
(Aspect 10)
In the mobile type non-contact power feeding device according to
aspect 8, the crossover coil is provided in such a manner that a
magnetic field is generated from the units formed by the crossover
alternately in the plus and minus directions.
(Aspect 11)
In the mobile type non-contact power feeding device according to
aspect 10, the crossover coil is set in such a manner that the area
of the units generating a magnetic field in the plus direction is
equal to that of the units generating a magnetic field in the minus
direction.
(Aspect 12)
In the mobile type non-contact power feeding device according to
aspect 8, a repeating coil of a repeating circuit is disposed
corresponding to the power receiving coil of the power receiving
side circuit.
The repeating circuit is independent of the power receiving circuit
and the repeating coil resonates with a capacitor disposed in the
repeating circuit and moves together with the power receiving
coil.
(Aspect 13)
In the mobile type non-contact power feeding device according to
aspect 8, power feeding is effected by a side power feeding method
whereby the power transmission coil of the power feeding side
circuit and the repeating coil of the repeating circuit
corresponding to the power transmission coil are fixedly disposed
on the side of an upright roadside section relative to a road
surface or a ground surface.
(Aspect 14)
In the mobile type non-contact power feeding device according to
aspect 8, power feeding is effected by a lower power feeding method
whereby the power transmission coil of the power feeding side
circuit and the repeating coil of the repeating circuit
corresponding to the power transmission coil are fixedly disposed
on the side of a road surface or a ground surface.
(Aspect 15)
In the mobile type non-contact power feeding device according to
aspect 8, the power receiving side circuit such as the power
receiving coil is mounted on a vehicle such as an automobile and
other movable body.
Operation and the like of the present invention will now be
described in the following items (1) through (10).
(1) In this non-contact power feeding device, power feeding is
effected by a mobile method.
(2) The non-contact power feeding device is provided in such a
manner that, in the case of power feeding, a power transmission
coil and/or its repeating coil and a power receiving coil and/or
its repeating coil are electromagnetically coupled through an air
gap.
(3) In this manner, in this non-contact power feeding device, power
is fed from a power feeding side to a power receiving side based on
a mutual induction effect of magnetic induction.
(4) In this non-contact power feeding device, a high frequency
magnetic field is strongly formed to strongly radiate the
electromagnetic waves by a power transmission coil of the power
feeding side formed in a long and massive loop shape or a repeating
coil of the power feeding side.
(5) In the present invention, a crossover coil is adopted to serve
as the power transmission coil or the repeating coil. The direction
of a magnetic field generated for each unit formed by the crossover
of the crossover coil is alternately reversed to provide reverse
polarity.
(6) Thus, each magnetic field and the electromagnetic waves
radiated toward a neighboring area, once propagated, overlap,
interfere, and cancel each other by diffusion and are greatly
weakened.
(7) Since a resonant repeating method is adopted in this
non-contact power feeding device, it is possible to make the air
gap large without losing electric energy.
(8) In this non-contact power feeding device, a repeating coil of a
resonant repeating circuit is disposed on a power feeding side
and/or a power receiving side.
(9) Accordingly, the high frequency magnetic field is formed more
strongly to radiate the electromagnetic waves more strongly, but
because of adoption of the crossover coil, the intensity of
electromagnetic waves in the neighboring area can be surely
lowered.
(10) The mobile type non-contact power feeding device of the
present invention has the following first, second and third
effects.
(First Effect)
First, in the present invention, a risk of electromagnetic
pollution can be prevented. A crossover coil is adopted in the
mobile type non-contact power feeding device according to the
present invention to serve as a power transmission coil of the
power feeding side or a repeating coil of the repeating circuit. A
magnetic field is formed and radiated toward a neighboring area,
and once propagated to the neighboring area, the individual
electromagnetic waves cancel each other and are weakened by
diffusion to greatly lower their intensity.
Accordingly, an adverse effect on the environment of the
neighboring area can be prevented with certainty. As in the
conventional non-contact power feeding device of this kind, a risk
of generating electromagnetic pollution, such as a risk of
generating electromagnetic disturbance and electronic jamming and a
risk of creating a functional disorder (dysfunction) on human
bodies, in an area which is tens of meters to hundreds of meters
away, can be avoided.
(Second Effect)
Second, expansion of the air gap can be realized in the present
invention.
For the mobile type non-contact power feeding device of the present
invention, a resonant repeating method is adopted between a power
transmission coil of a power feeding side and a power receiving
coil of the power receiving side.
With this arrangement, it is possible to make the air gap large
without losing electric power. In this non-contact power feeding
device, it is therefore possible to feed a large amount of power of
several kW order or more even over a large gap of, for example,
several meters.
In this case, the stronger magnetic field is formed to radiate
stronger electromagnetic waves, but a risk of generating
electromagnetic pollution can be avoided by adopting the crossover
coil.
(Third Effect)
The present invention can contribute to the widespread utilization
of an electric vehicle. In the mobile type non-contact power
feeding device of the present invention, as described above, the
electromagnetic pollution can not only be avoided, but expansion of
the air gap can also be realized. Accordingly, the mobile type
non-contact power feeding device can be readily adopted as an easy
and safe means for feeding power to the electric vehicle which is
running on an express highway and other roads.
However, a bottleneck of the widespread utilization of the electric
vehicle is, as is well known, the high-cost and heavy-weight
structure of a battery mounted thereon. On the contrary, if the
non-contact power feeding device of the present invention is
adopted, it is possible to readily charge a battery along the way
and as a result, small capacity, downsizing, cost reduction,
reduction in weight, etc. of the battery of the electric vehicle
can be realized.
For example, by continuously installing the power feeding side of
the non-contact power feeding device of the present invention in
place on the express highway to charge the battery of the running
electric vehicle on the power receiving side, it is also possible
to cause the electric vehicle on the express highway to run over a
long distance.
In this manner, the present invention can greatly contribute to the
power feeding to the electric vehicle running on the express
highway and its widespread utilization.
As is obvious from the first, second and third effects described
above, the present invention has a great effect in that all the
problems of the conventional non-contact power feeding device of
this kind can be solved.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will become more apparent from the following description
when taken in conjunction with the accompanying drawings.
FIG. 1 is an explanatory perspective view of a mobile type
non-contact power feeding device according to the present
invention, wherein FIG. 1A is a first embodiment and FIG. 1B is a
second embodiment;
FIG. 2 is an explanatory perspective view of the mobile type
non-contact power feeding device according to the present
invention, wherein FIG. 2A is a third embodiment and FIG. 2B is a
fourth embodiment;
FIG. 3 is an explanatory perspective view of the mobile type
non-contact power feeding device according to the present
invention, wherein FIG. 3A is a fifth embodiment and FIG. 3B is a
sixth embodiment;
FIG. 4 is an explanatory perspective view of a crossover coil of
the mobile type non-contact power feeding device, wherein FIG. 4A
shows its basic principle and FIG. 4B shows the positional
relationship in which power feeding is difficult;
FIG. 5 is an explanatory perspective view of the mobile type
non-contact power feeding device according to the present
invention, wherein a power feeding method on a road is shown;
and
FIG. 6 shows one example of a lower power feeding method, wherein
FIG. 6A is an explanatory side view and FIG. 6B is an explanatory
view of the essential part thereof.
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will now be fully
described hereunder.
(Non-Contact Power Feeding Device 1)
First, a mobile type non-contact power feeding device 1 is
generally described with reference to FIG. 6. The non-contact power
feeding device 1 is provided to feed electric power from a power
transmission coil 3 of a power feeding side circuit 2 to a power
receiving coil 5 of a power receiving side circuit 4 through an air
gap A based on a mutual induction effect of the electromagnetic
induction.
The non-contact power feeding device is provided in such a manner
that power feeding is effected by a mobile power feeding method
whereby, in the case of power feeding, the power receiving coil 5
is moved corresponding to the stationary power transmission coil 3
through the air gap A. The power transmission coil 3 and the power
receiving coil 5 are respectively formed in a loop-shaped flat
structure.
Such a non-contact power feeding device 1 will be further described
in detail. The power feeding side circuit 2 of a primary side, that
is, a power feeding side and a track side, is fixedly disposed on a
ground surface, a road surface, a floor surface or another part
above a ground 6 at a power feeding stand or other power feeding
area.
The power receiving side circuit 4 of the secondary side, that is,
the power receiving side and a pickup side, is mounted on a vehicle
7 such as an electric vehicle and an electric train, or other
movable body. The power receiving side circuit 4 is available not
only for driving, but also for non-driving. The power receiving
side circuit 4 is mainly connected to a car-mounted battery 8 as
shown in FIG. 6, but it can also be connected directly to various
types of loads L (see FIGS. 1 through 4).
The power transmission coil 3 of the power feeding side circuit 2
is connected to a power source 9 in which a high frequency inverter
is used. The power receiving coil 5 of the power receiving side
circuit 4 can be connected to a battery 8 in an example as shown in
FIG. 6, wherein a running motor 10 is driven by the battery 8
charged by a power feeding operation. Reference numeral 11 of the
figure is a converter for converting an alternating current to a
direct current and 12 is an inverter for converting the direct
current to the alternating current.
The power transmission coil 3 and the power receiving coil 5
respectively have a flat structure on which an insulated coil
conducting wire is wound, for example, a number of times, in a loop
shape on the same surface and are formed in a long rectangular
circular shape along the direction of movement B of a movable body.
The power transmission coil 3 is provided to have the same width as
that of the power receiving coil 5 and is formed in a long and
massive loop shape which is several times to tens of times longer
than the power receiving coil 5. For example, the power
transmission coil 3 can have the size of 5 m.times.28 cm, while the
power receiving coil 5 can have the size of 1 m.times.28 cm.
The power feeding operation is effected by a mobile power feeding
method. In other words, in the case of power feeding, the power
receiving coil 5 of the power receiving side circuit 4 moves or
runs in a closely corresponding manner to the long and massive
power transmission coil 3 of the power feeding side circuit 2 and
the power is fed through an air gap A with no contact.
Next, a mutual induction effect of electromagnetic induction will
now be described. It is publicly known and used in practice that,
in the case of power feeding between the power transmission coil 3
and the power receiving coil 5a, a magnetic flux is formed in the
power transmission coil 3 to generate induced electromotive force
in the power receiving coil 5, thereby feeding electric power to
the power receiving coil 5 from the power transmission coil 3.
In other words, by applying a high frequency alternating current
of, for example, about 10 kHz to 100 kHz to the power transmission
coil 3 of the power feeding side circuit 2 by a power source 9 as
an exciting current, a magnetic field is generated around the coil
conducting wire of the power transmission coil 5 and a magnetic
flux is formed in the direction perpendicular to the surface of the
coil. The magnetic flux goes through the power receiving coil 5 of
the power receiving side circuit 4 for interlinkage, wherein the
induced electromotive force is generated to form the magnetic
field, thereby feeding and receiving the electric power using the
magnetic field formed.
In the non-contact power feeding device 1, a magnetic path of a
magnetic flux is formed in the air gap A between the power
transmission coil 3 and the power receiving coil 5 to provide
electromagnetic coupling between both circuits of the power
transmission coil 3 and the power receiving coil 5. In this manner,
a power supply of several kW or more, for example, tens of kW to
hundreds of kW is effected.
The mobile type power feeding device 1 is as described above.
(First Embodiment of the Present Invention)
A mobile type non-contact power feeding device 1 of the present
invention will be described below. First, a first embodiment of the
present invention will be described with reference to FIG. 1A.
In the non-contact power feeding device 1 of the first embodiment,
a crossover coil C is adopted to serve as a power transmission coil
3 of a power feeding side circuit 2 on the power feeding side.
In the case of power feeding, a power transmission coil 3
consisting of the crossover coil C on the power feeding side and a
power receiving coil 5 on the power receiving side are provided to
form a magnetic path of magnetic flux in an air gap A between them.
In this manner, the power transmission coil 3 (the crossover coil
C) and the power receiving coil 5 are electromagnetically coupled
to effect power feeding (refer to the above general description of
the non-contact power feeding device 1).
The crossover coil C will now be described with reference to FIG.
4A. The crossover coil C on the power feeding side is formed in a
long loop shape along the direction of movement B of the power
receiving side and is crossed on the way to provide a plurality of
units D by the crossover.
The crossover coil C conforms to the above description of the power
transmission coil 3 and is formed in a flat structure, in which an
insulated coil conducting wire is wound, for example, a plurality
of turns (shown as one line in FIGS. 1A and 4A and other figures),
in a long and massive loop shape on the same surface. The crossover
coil C is crossed at crossover points E on the way to provide a
plurality of units D which is divided and compartmentalized.
The number of crossover points E, that is, the number of
crossovers, can be singular or plural. In FIGS. 1, 4A and other
figures, the number of crossovers is 3 to provide 4 units D. An are
of each unit D formed by the crossover (i.e., an area of a flat
surface surrounded by an insulated coil conducting wire of the unit
D) is set to be common, that is, to be same in FIGS. 1A, 4A and
other figures, but it can be set to be different.
In any case, for the crossover coil C as shown in FIG. 4A, the
direction of magnetic field F generated between each unit D formed
and connected in series by the crossover is alternately reversed in
the plus direction and in the minus direction.
In other words, when an electric current is fed to the crossover
coil C, the magnetic field corresponding to the current is
generated, but the direction of current is mutually reversed for
each unit D adjacently formed by the crossover and as a result, the
direction of magnetic field is alternately reversed in the plus
direction and in the minus direction. Namely, for the crossover
coil C, a north pole and a south pole of the magnetic field is
reversed for each adjacent unit connected by the crossover to
generate the magnetic field in the reverse direction.
The crossover coil C is set in such a manner that the area of the
units D generating a magnetic field in the plus direction is equal
to that of the units D generating the magnetic field in the minus
direction.
In other words, the crossover coil C is provided so that the total
area of the unit D of the magnetic field in the plus direction is
equal to that of the units D of the magnetic field in the minus
direction. It is to be noted that "equality" of the total area
includes not only a case of perfect matching, but also a case of
small difference. In FIGS. 1A, 4A and other figures, the area of
each unit D is common, that is, equal as described above and thus,
the units D in the plus direction and the units D in the minus
direction are the same in number, that is, two each.
In the first embodiment, such a crossover coil C is adopted (to
serve) as a transmission coil 3. The first embodiment is as
described above.
(Second Embodiment)
Next, the second embodiment of the present invention will now be
described with reference to FIG. 1B. In the non-contact power
feeding device 1 of the second embodiment, in addition to the
structure of the first embodiment, a repeating coil 14 of a
repeating circuit 13 is disposed corresponding to the power
receiving coil 5 of the power receiving side circuit 4.
The repeating circuit 13 is independent of the power receiving side
circuit 4 and its repeating coil 14 resonates with a capacitor 15
disposed in the repeating circuit 13.
The non-contact power feeding device 1 of such a second embodiment
will be described further. In the second embodiment, for the power
receiving side, the repeating coil 14 of the power receiving side
repeating circuit 13 is disposed on the side of an air gap A of the
power receiving coil 5 of the power receiving side circuit 4 in a
long loop shape closely corresponding to and matching the size of
the power receiving coil 5.
The repeating circuit 13 composed of the repeating coil 14 and the
capacitor 15 consists of a circuit which is independent of the
power receiving side circuit 4 and resonates in a resonant
frequency matching the operating frequency of the power source 9 of
the power feeding side circuit 2, that is, the operating frequency
of the entire circuit. In this specification, the resonant circuit
also includes a magnetic resonance circuit in which an extremely
high frequency is used.
In the non-contact power feeding device according to the second
embodiment, since the repeating coil 14 resonates with the
capacitor 15 in the case of power feeding, a magnetic path of a
magnetic flux is formed, electromagnetically coupled and power
feeding is effected between the power transmission coil 3 (the
crossover coil C), and the repeating coil 14 and the power
receiving coil 5, even though there is a large air gap A between
them.
In this manner, a resonant repeating method is adopted together
with the crossover coil C in the second embodiment. In the second
embodiment, since the structures of the power transmission coil 3
(the crossover coil C) and other components conform to those of the
first embodiment described above, these are given the same
reference numerals and their descriptions are omitted.
The second embodiment is described above.
(Third Embodiment)
Next, a third embodiment of the present invention will be described
with reference to FIG. 2A. In the non-contact power feeding device
1 of the third embodiment, a repeating coil 17 of a repeating
circuit 16 is fixedly disposed corresponding to the power
transmission coil 4. The repeating circuit 16 is independent of the
power feeding side circuit 2, and the repeating coil 17 resonates
with a capacitor 18 disposed in the repeating circuit 16.
In the case of power feeding operation, the power receiving coil 5
moves corresponding to the repeating coil 17 of the power feeding
side through an air gap A.
Unlike the first and second embodiments, the crossover coil C is
not adopted as the power transmission coil 3 of the power feeding
side circuit 2. Instead, the crossover coil C is adopted as the
repeating coil 17 of the repeating circuit 16.
The non-contact power feeding device 1 of the third embodiment will
be further described. In the third embodiment, for the power
feeding side, the repeating coil 17 of the power feeding side
repeating circuit 16 is disposed to closely correspond to a side of
an air gap A of the power transmission coil 3 of the power feeding
side circuit 2.
The repeating circuit 16 consisting of the repeating coil 17 and
the capacitor 18 is composed of a circuit independent of the power
feeding side circuit 2 and also composed of a resonant circuit
which resonates in a resonant frequency of an entire circuit
matching the operational frequency of the power source 9 of the
power feeding side circuit 2.
In the third embodiment, unlike the first and second embodiments
described above, the crossover coil C is adopted as the repeating
coil 17 of such a repeating circuit 16. Refer to the detailed
description of the first embodiment for the crossover coil C. In
the third embodiment, the repeating circuit 16 is provided with
only one capacitor 18 which is common to each unit D of the
repeating coil 17 (the crossover coil C).
Further, in this third embodiment, the power transmission coil 3 of
the power feeding side circuit 2 is not formed in the long and
massive loop shape as in the general example and the first and
second embodiments described above, but in a short and small
rectangular shape, in view of the fact that the crossover coil C of
the long and massive loop shape is used as the repeating coil
17.
Reference numeral 19 is a capacitor which is disposed in the power
feeding side circuit 2. With this arrangement, the power feeding
side circuit 2 composed of the power transmission coil 3 and the
capacitor 19 becomes a resonant circuit which resonates in a
resonant frequency matching the operational frequency of the power
source 9. In the embodiment shown in FIG. 2A, the capacitor 9 is
disposed in parallel, but it can also be disposed in series in the
case where the power transmission coil 3 is large, its inductance
becomes large, and it is difficult to apply electric current (refer
to fifth and sixth embodiments of FIG. 3 described later).
Referring to this third embodiment, in the case of power feeding,
since the power transmission coil 3 resonates with the capacitor 19
and the repeating coil 17 (the crossover coil C) resonates with the
capacitor 18, a magnetic path of a magnetic flux is surely formed,
electromagnetically coupled, and power feeding is effected between
the power transmission coil 3 and the repeating coil 17 (crossover
coil C) on the power feeding side, and the power receiving coil 5
on the power receiving side, even though there is a large air gap A
between them.
In this manner, a resonant repeating method is adopted with the
crossover coil C in the third embodiment. Since the structures of
the crossover coil C and other components in the third embodiment
conform to those of the first embodiment described above, these are
given the same reference numerals and their descriptions are
omitted.
The third embodiment is as described above.
(Fourth Embodiment)
Next, a fourth embodiment of the present invention will now be
described with reference to FIG. 2B. In the non-contact power
feeding device 1 of the fourth embodiment, a power receiving side
repeating circuit 13 as in the second embodiment is disposed in
addition to the structure of the third embodiment described
above.
In this manner, a number of resonant repeating methods is adopted
together with the crossover coil C in the fourth embodiment. Since
the structures of the repeating coil 17 (crossover coil C), the
repeating coil 14 and other components in the fourth embodiment
conform to those of the second and third embodiments described
above, these are given the same reference numerals and their
descriptions are omitted.
The fourth embodiment is as described above.
(Fifth Embodiment)
Next, a fifth embodiment of the present invention will be described
with reference to FIG. 3A. In the non-contact power feeding device
1 of the fifth embodiment, the capacitor 18 of the repeating
circuit 16 is disposed in at least two units of the repeating coil
17 (the crossover coil C), in addition to the structure of the
third embodiment described above. As typically shown in FIG. 3A,
the capacitor 18 is disposed for each unit D.
Although the repeating circuit 16 of the third embodiment described
above is provided with only one capacitor 18 which is common to
each unit D, a number of capacitors 18 is disposed in the fifth
embodiment.
The reason for disposing a number of capacitors 18 is as follows.
If the repeating coil 17 (the crossover coil C) of the repeating
circuit 16 consisting of the resonant circuit becomes long along
the direction of movement B, the inductance becomes large. In order
to keep the resonant frequency constant, it is necessary to
decrease a capacity of the capacitor 18 for resonance in inverse
proportion to the amount of inductance.
The capacity of the capacitor 18 in a circuit is inversely
proportional to the number of series connection. It is therefore
possible to keep the resonant frequency constant as originally
expected by increasing the number of series connections of the
capacitor 18 of the same capacity and by decreasing the capacity of
the entire capacitor 18.
For the reason described above, the number of series connections of
the capacitor 18 is increased in the fifth embodiment. As a
representative example, the capacitor 18 is disposed for each unit
D of the repeating coil (the crossover coil C). With this
arrangement, there is the disadvantage that further length and
massiveness of the repeating coil 17 (the crossover coil C) can be
stably realized.
In this manner, in FIG. 5, the crossover coil C and a resonant
repeating method are adopted and a number of capacitors 18 for
resonance is used. Since the structures of the crossover coil C and
other components conform to those of FIG. 3 described above, these
are given the same reference numerals and their descriptions are
omitted.
The fifth embodiment is as described above.
(Sixth Embodiment)
Next, a sixth embodiment of the present invention will be described
with reference to FIG. 3B. In the non-contact power feeding device
1 of the sixth embodiment, the power receiving side repeating
circuit 13 as in the second and fourth embodiments is disposed in
addition to the structure of the fifth embodiment described
above.
In this manner, in the sixth embodiment, a number of resonant
repeating methods are adopted with the crossover coil C. Since the
structures of the repeating coil 17 (the crossover coil C), the
repeating coil 14 and other components in the sixth embodiment
conform to those of the second and fifth embodiments described
above, these are given the same reference numerals and their
descriptions are omitted.
The sixth embodiment is as described above.
(Disposition Etc. of the Non-Contact Power Feeding Device 1)
Next, disposition and the like of the mobile type non-contact power
feeding device 1 will now be described with reference to FIGS. 5
and 6.
First, a secondary side of the non-contact power feeding device 1,
that is, a power receiving side or a pickup side, in other words, a
power receiving side circuit 4 such as a power receiving coil 5 and
a power receiving side repeating circuit 13 such as a repeating
coil 14 are mounted on a vehicle such as an automobile or other
movable body.
The primary side of the non-contact power feeding device 1, that
is, the power feeding side or the track side, in other words, the
power feeding side circuit 2 such as the power source 9 and the
power transmission coil 3 and the power feeding side repeating
circuit 16 such the repeating coil 17 are fixedly disposed on a
ground surface, a road surface, a floor surface or another part
above the ground 6.
Disposition and the like of the mobile type non-contact power
feeding device 1 on the power feeding side will be further
described. A side power feeding method and a lower power feeding
method are representative power feeding methods by the mobile type
non-contact power feeding device 1.
Referring to the side power feeding method, the power transmission
coil 3 (the crossover coil C) and the repeating coil 17 (the
crossover coil C) on the power feeding side are fixedly disposed on
the side of an upright roadside section 21 such as a wall surface
of a road shoulder relative to the road surface or the ground
surface of a road 20 on the side of a part above the ground 6
(refer to a left lane of FIG. 5 for the third through sixth
embodiments described above). Of course, for the power receiving
side, the power receiving coil 5 and the repeating coil 14 are
disposed on the side section of the vehicle 7 such as an electric
vehicle or other movable body.
In the case of the lower power feeding method, the power
transmission coil 3 and the repeating coil 17 on the power feeding
side are fixedly disposed by an embedding method or the like on a
road surface or a ground surface of a road 20 on the side of a part
above the ground 6 (refer to FIG. 6 for the first and second
embodiments described above and refer to a right lane of FIG. 5 for
the third through sixth embodiments). Of course, for the power
receiving side, the power receiving coil 5 and the repeating coil
14 are disposed on the bottom section of the vehicle 7 such as an
electric vehicle or other movable body.
The side power feeding method is superior to the lower power
feeding method in installation cost, maintenance of reliability and
the like. Reference numeral 22 of FIG. 5 is a center divider. The
configuration in which the power transmission coil 3 and the
repeating coil 17 are fixedly disposed on the center divider is
also part of the side power feeding method.
At any rate, as shown in FIG. 5, there are many cases where a
number of power feeding sides is disposed along the direction of
running, that is, the direction of movement B, of the vehicle 7
such as the electric vehicle.
Each unit D of each power transmission coil 3 (the crossover coil
C) on the power feeding side and each unit D of each repeating coil
17 (the crossover coil C) on the power feeding side are installed
in a row, that is, in a substantially belt-like pattern, over the
whole length of a power feeding area along the direction of
movement B. The entire length varies from tens of meters to
hundreds of meters.
The disposition etc. of the non-contact power feeding device 1 is
as described above.
(Operation Etc.)
The mobile type non-contact power feeding 1 of the present
invention is constructed as described above. Operation, etc. of the
present invention will now be described in the following items (1)
through (10).
(1) In the non-contact power feeding device 1, a power feeding is
conducted by a mobile power feeding method. In other words, in the
case of power feeding, the secondary side mounted on the vehicle 7
such as the electric vehicle or other movable body, that is, the
power receiving coil 5 (refer to the first through sixth
embodiments) and the repeating coil 14 (refer to the second, fourth
and sixth embodiments) on the power receiving side or the pickup
side moves or runs. These power receiving coil 5 and repeating coil
14 move or run, with no contact through an air gap, closely
corresponding to the primary side fixedly disposed on the road 20
or another part above ground 6 side, that is, the power
transmission coil 3 (refer to first and second embodiments) and the
repeating coil 17 (refer to the third through sixth embodiments) on
the power feeding side or the track side.
(2) In the case of power feeding, on the power feeding side of the
non-contact power feeding device 1, a high frequency alternating
current is applied from a power source 9 to the power transmission
coil 3 of the power feeding side circuit 2 as an exciting current.
In this manner, a magnetic path of a magnetic flux is formed and
electromagnetically coupled between the power feeding side and the
power receiving side through the air gap A.
In other words, the magnetic path of the magnetic flux is formed
and electromagnetically coupled between the power transmission coil
3 (the crossover coil C) and the power receiving coil 5 (refer to
first embodiment), between the power transmission coil 3 (the
crossover coil C), the repeating coil 14 and the power receiving
coil 5 (refer to the second embodiment), between the power
transmission coil 3, the repeating coil 17 (the crossover coil C)
and the power receiving coil 5 (refer to the third and fifth
embodiments), or between the power transmission coil 3, the
repeating coil 17 (the crossover coil C), the repeating coil 14 and
the power receiving coil 5 (refer to the fourth and sixth
embodiments).
(3) In this manner, the non-contact power feeding device 1 is
provided in such a manner that power is fed from the power
transmission coil 3 and/or the repeating coil 17 to the repeating
coil 14 and/or the power receiving coil 5 based on a mutual
induction effect of electromagnetic induction. In other words,
power feeding is conducted from the primary side, that is, the
power feeding side or the track side to the secondary side, that
is, the power receiving side or the pickup side. Specifically,
power is sequentially fed from each unit D (the power transmission
coil 3 and the repeating coil 17) of the long and massive crossover
coil C to the repeating coil 14 and the power receiving coil 5
which are moving closely corresponding to each unit D.
(4) A high frequency alternating current of about 10 kHz to 100 kHz
is used in the non-contact power feeding device 1 of this type.
Since power feeding is conducted based on the mutual induction
effect of electromagnetic induction using such a high frequency
alternating current, a high frequency magnetic field of a large
density (an alternating magnetic field) is formed to radiate strong
high-frequency electromagnetic waves.
Further, the power transmission coil 3 or the repeating coil 17 on
the power feeding side adapted to irradiate such a high frequency
magnetic field and high frequency electromagnetic waves is formed
in a long and massive loop shape and is provided in a row, that is,
in a substantially belt shape, between tens of meter and hundreds
of meters over the entire length of the power feeding area.
(5) Thus, in the present invention, the crossover coil C is adopted
as the power transmission coil 3 (refer to the first and second
embodiments) or the crossover coil C is adopted as the repeating
coil 17 (refer to the third to sixth embodiments).
The crossover coil C is provided in such a manner that the
direction of the magnetic field generated from each unit D formed
by the crossover becomes a reverse polar zone and is alternately
reversed in the plus direction and in the minus direction.
(6) After formation of each unit D, the magnetic field radiated
outside and gradually diffused from a power feeding area in which a
power feeding side of the non-contact power feeding device 1 is
provided to a neighboring area, for example, tens of meters to
hundreds of meters away, is cancelled out and weakened in the
neighboring area. In other words, the magnetic field in the plus
direction and the magnetic field in the minus direction which are
adjacent to each other, when propagated to the neighboring area,
spread, overlap, and interfere with each other by diffusion. Both
magnetic fields form a synthetic magnetic field and cancel each
other out based on the reverse polarity and as a result, the
magnetic field density greatly decreases.
Accordingly, all the electromagnetic waves radiated out of the
power feeding side of the non-contact power feeding device 1 are
greatly reduced to significantly lower the strength in the area
which is away from the non-contact power feeding device 1. Thus,
the electric field and the magnetic field diffused outside, that
is, an electric line of force and a magnetic line of force are
quantitatively reduced and the strength is qualitatively
reduced.
As described above, since cancelling of the magnetic field in the
plus direction and the magnetic field in the minus direction is
important, it is effective in realization of operation that the
crossover coil C is set so that the entire area of each unit D
generating the magnetic field in the plus direction is equal to
that of each unit D generating the magnetic field in the minus
direction. Being equal in this case includes not only a case of
perfect matching, but also a case of a small difference.
(7) On the other hand, a resonant repeating method is adopted in
this non-contact power feeding device 1. Namely, the non-contact
power feeding device 1 is provided in such a manner that the
repeating coil 17 (the crossover coil C) of the resonant repeating
circuit 16 (refer to the third to sixth embodiments) and the
repeating coil 14 of the resonant repeating circuit 13 (refer to
the second, fourth and sixth embodiments) are disposed between the
power transmission coil 3 of the power feeding side and the power
receiving coil 5 of the power receiving side to provide
electromagnetic coupling between them. In this non-contact power
feeding device 1, a large exciting reactive power is fed to a
magnetic path of the air gap A by resonance.
When the resonant repeating method is adopted, the gap power
feeding efficiency can be improved by the resonance and the air gap
A can be made large without wasting the electric energy
supplied.
(8) Consideration is now made for the air gap A of each embodiment
of the present invention. As compared to the first embodiment, the
repeating coil 14 resonating with the power transmission coil 3
(the crossover coil C) of the power feeding side is used on the
power receiving side in the second embodiment. It is therefore
possible to make the electromagnetic coupling between them more
definite even though the air gap A is large.
Further, since the repeating coil 14 is closely located to face the
power receiving coil 5, the degree of electromagnetic coupling
between them is extremely high. Referring to the second embodiment,
the air gap A can be made larger by use of the repeating coil
14.
In the third and fifth embodiments, since the power transmission
coil 3 and the repeating coil 17 (the crossover coil C), which are
electromagnetically coupled by resonance, are used on the power
feeding side, the air gap A can be made large by their use.
Further, in the fourth and sixth embodiments, since the resonating
repeating coil 14 is added to the power receiving side, the air gap
A can be made larger.
(9) With the adoption of such a resonant repeating method, a high
frequency alternating current of more than 10 kHz, for example, of
about 10 kHz to 100 kHz, is used in this non-contact power feeding
device 1 and thus, stronger magnetic field is formed to radiate
stronger electromagnetic waves.
However, by adopting the crossover coil C described above, the
intensity of the magnetic field and electromagnetic waves radiated
to the neighboring area can be reduced with certainty. Thus, an
adverse effect of the electromagnetic waves on the neighboring area
can be avoided.
(10) For the crossover coil C (the power transmission coil 3 or the
repeating coil 17), in the case where the mobile power receiving
coil 5 or repeating coil 14 is closely located to correspond to the
crossover point E, power feeding becomes difficult temporarily.
Further, unlike each unit D area, a synthetic magnetic field, in
which the magnetic field in the plus direction and the magnetic
field in the minus direction cancel each other, is formed at once
at the crossover point E to instantaneously generate a flat zero of
power feeding.
In other words, for each magnetic field formed in each unit D area
of the crossover coil C (the power transmission coil 3 or the
repeating coil 17), it is not possible in terms of position for the
magnetic field in the plus direction and the magnetic field in the
minus direction to interfere and immediately cancel at the time of
formation. Thus, smooth power feeding is conducted, with time, to
the power receiving coil 5 or the repeating coil 14, which moves in
a closely corresponding manner, by each magnetic field formed in
each unit D area.
At the crossover point E, as in the neighboring area described
above, a synthetic magnetic field, in which the magnetic field in
the plus direction and the magnetic field in the minus direction
interfere and cancel each other, is formed. Thus, such an
interfering and cancelling synthetic magnetic field is immediately
formed at the crossover point E at the time of formation of the
magnetic field, while, in the neighboring area, it is only formed
at the time when the magnetic field formed in each unit D area is
radiated and diffused, in other words, at the time when the
magnetic field is propagated to the remote neighboring area.
The vehicle 7 such as the electric vehicle can pass through such a
crossover point E by the power of a battery 8 which has been
already charged and the influence can be almost ignored.
Operation and the like are as described above.
* * * * *